The 990-square-foot residence is only 8-foot-4 at its widest spot, but is rich in history, the New York Post reported Thursday.
Edna St. Vincent Millay penned her Pulitzer Prize-winning poem "Ballad of the Harp-Weaver" between its narrow walls in 1923 and 1924.
Actors Cary Grant and John Barrymore visited there.
Anthropologist Margaret Mead lived there, as did "Stone Soup" children's author Ann McGovern.
McGovern called the house her "doll house," and it inspired her to write "Mr. Skinners Skinny House," about a man living in the narrowest house in the city trying to find a roommate.
Architectural preservationist Christopher Dobbs purchased the house in 1994 for $270,000.
He sold the house in 2000 to Steven Balsamo for $1.6 million, and three years ago it sold again for $2.175 million.
City records indicate the townhouse's latest buyer is George Gund.
The three-bedroom house was built in 1873 and features floor-to-ceiling French doors that open to a back yard that is 42-feet, 4-inches long. At 9-feet 9-inches wide, it's wider than the house.